Pump Impeller Axial Pin Sealing and Guidance

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Solution Overview

Problem

Existing pumps for contaminated liquids, such as sewage, often malfunction due to solid matter obstructing the impeller, leading to costly maintenance and potential damage from liquid entering the impeller's cylinder-shaped recess, and are prone to tilting under asymmetric forces.

Innovation Solution

Incorporating an axially extending pin within the impeller's hole to prevent liquid and solid matter from entering the recess, combined with a liquid sealing mechanism and a sleeve connected to the drive shaft unit to enhance axial guidance and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the impeller and impeller seat are positioned at a fixed distance from each other, then the pump structure is simple, but large pieces of solid matter cannot pass through and may cause the impeller to wedge

Engineering Contradiction:
Improvepump structure simplicityVSAvoidability to pass solid matter
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The impeller is designed to be displaceable in the axial direction relative to the drive shaft unit, transforming the fixed structure into a dynamic one. This allows the impeller to move axially to accommodate large solid matter pieces during operation, while returning to its normal position during pumping, thus resolving the contradiction between structural simplicity and adaptability to solid matter passage

Inventive Principle:
Principle #15Dynamics

2Reliability

If a plug is used to prevent liquid from entering the cylinder-shaped recess, then liquid entry is prevented, but the plug may be overlooked during servicing and corrosion occurs

Engineering Contradiction:
Improveprotection against liquid entryVSAvoidservice reliability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The harmful function of the through-hole (allowing liquid entry) is eliminated by extracting the hole itself and replacing it with a pin structure. The pin serves as both a connection element and a protective barrier, removing the need for separate plugs and eliminating the risk of oversight during servicing

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the interface between the impeller and drive shaft unit has relatively small extension, then the device complexity is reduced, but the impeller runs the risk of becoming tilted under asymmetric force

Engineering Contradiction:
Improveinterface complexityVSAvoidimpeller stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The pin is designed with asymmetric features including a conical upper end for tool engagement and a specific radial abutment configuration. This asymmetric design provides enhanced guidance and anti-tilting functionality while maintaining relatively simple construction, resolving the contradiction between device complexity and impeller stability

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3033528B1Pump for pumping liquid as well as an impeller assembly
Publication Date: 2020.07.01 XYLEM EURO GMBH
  • EP3033528B1 patent drawingFigure 1
  • EP3033528B1 patent drawingFigure 2~3
  • EP3033528B1 patent drawingFigure 4~6

AI summary

The invention relates to an impeller assembly and a pump for pumping a liquid, comprising a pump chamber and an impeller (4) arranged to rotate in said pump chamber, said impeller being suspended in a lower end (5) of an axially extending drive shaft unit (6), wherein said lower end (5) of the drive shaft unit (6) is received in a cylinder-shaped recess (10) of the impeller (4), wherein the impeller (4) is displaceable back and forth in the axial direction in relation to the drive shaft unit (6). The impeller further comprises an axially extending hole (21) that connects the cylinder-shaped recess (10) and the pump chamber and that the drive shaft unit (6) comprises an axially extending pin (22) that projects from said lower end (5) of the drive shaft unit (6), wherein said pin (22) is arranged in said hole (21).